package filter;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 * Servlet Filter implementation class EncodingFilter
 */
public class EncodingFilter implements Filter {

	private String charEncoding = null;
	
    /**
     * Default constructor. 
     */
    public EncodingFilter() {
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see Filter#init(FilterConfig)
	 */
	public void init(FilterConfig fConfig) throws ServletException {
		
		charEncoding = fConfig.getInitParameter("encoding");
		
		System.out.println("charEncoding = " + charEncoding);
		
		if (charEncoding == null) {
			throw new ServletException("EncodingFilter中的编码设置为空!!!");
		}
		
	}

	/**
	 * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
	 */
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		if (!charEncoding.equals(request.getCharacterEncoding())) {
			request.setCharacterEncoding(charEncoding);
		}
		response.setCharacterEncoding(charEncoding);
		chain.doFilter(request, response);
	}

	/**
	 * @see Filter#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}

}
